Saving many to many relationship tables in Asp.Net MVC - asp.net-mvc

I use Asp.Net MVC, Entity Framework. I have a form it looks like below.
Here, dropdownlist is filled from a table(types). Checkboxes is filled from another table(test). Tables are like below:
public class Types
{
public int TypesID{get;set;}
public string TestName { get; set; }
public string TestExplanation { get; set; }
public int TestTime { get; set; }
}
public class Tests
{
public int TestID{get;set;
public string Name { get; set; }
public string Code { get; set; }
}
public class Types_Tests
{
public int Types_TestsID{ get; set; }
public int TypesID { get; set; }
public int TestsID { get; set; }
public virtual Types Types { get; set; }
public virtual Tests Tests { get; set; }
}
Types_test table is relation table between Types and Tests. When I click Kaydet button, it shuld save type and checked tests. I made this operation using ViewBag, javascript and hdnvalue.I added checked checkboz values to a hdntext. I made saving process like below:
[HttpPost]
public ActionResult Index(string drpType, string hdntesttypes)
{
var TypeList = Types.GetAll();
ViewBag.TypesList = new SelectList(TypeList, "Id", "Name");
var testypeList = testTypes.GetAll();
ViewBag.TestTypesList = new SelectList(testypeList, "Id", "TestName");
GenericRepository<TestDisabledTypes> testDisabledRepository = new GenericRepository<TestDisabledTypes>(_context);
if (!string.IsNullOrEmpty(hdntesttypes))
{
string[] disabletypesArray = hdntesttypes.Split(',');
using (TransactionScope trns = new TransactionScope())
{
for (int i = 0; i < disabletypesArray.Length; i++)
{
Test_Types types = new Test_Types ();
types.TestTypesID = Convert.ToInt32(disabletypesArray[i]);
types.TypesID = Convert.ToInt32(drpType);
testDisabledRepository.Insert(types);
}
trns.Complete();
}
}
return View();
}
It wokrs. But I search better solution for this process. Can someone give me any idea?
Thanks.

If you don't need additional attributes for your entity class, you don't need create link table.
Just define the following class, and EF will generate the link table for you automatically.
public class Type
{
public int TypesID{get;set;}
public string TestName { get; set; }
public string TestExplanation { get; set; }
public int TestTime { get; set; }
public ICollection<Test> Tests { get; set; }
}
public class Test
{
public int TestID{get;set;
public string Name { get; set; }
public string Code { get; set; }
public ICollection<Type> Types {get;set;}
}

Well, in EntityFramework if you want to create a many to many relation object you need to create new object of "linking" entity. Unfortunately, it is not possible to add first object, add second object and say "Guys, you are in many to many relationships. Are you happy then?" :) You need to create relation object, set appropriate fields in it (I think these are ids of two objects itself) and add it to relation collection (entity) in your model. But before doing so you need to be sure that objects with data you are linking with are already exists in database. Otherwise you'll get an error
Also it's not necessary to create manually transaction because EF does it for you automatically each time you get/save your data

Related

Viewmodel set up Aspt.net MVC 6

I'm having trouble understanding how to implement a ViewModel in Asp.net MVC, I have the following tables:
Form
ID, Data
Report
ID, FormID, Owner, Category, Status, SubmissionDate
ReportValues
ID, ReportID, Title, Value
I'm looking for a way to display and edit Report and ReportValues in the one ViewModel where ReportValues.ReportID = Report.ID
ReportValues will have multiple entries that relate to a Report.
I have had a look at similiar questions on here and tried following a tutorial ( http://techfunda.com/howto/262/list-data-using-viewmodel ) and coming up empty handed.
If you need any more information let me know and thanks in advance for any replies!
Your View Model is nothing more than a class. You can solve this many ways, but here's an example.
Create your 3 classes like you normally would.
public class Form
{
public int Id { get; set; }
public string Data { get; set; }
}
public class ReportValues
{
public int Id { get; set; }
public int ReportId { get; set; }
public string Title { get; set; }
public string Value { get; set; }
}
public class Report
{
public int Id { get; set; }
public int FormId { get; set; }
public string Owner { get; set; }
public string Category { get; set; }
public string Status { get; set; }
public DateTime SubmissionDate { get; set; }
}
Then, create your ViewModel class to include the three above classes like this.
public class ReportViewModel
{
public Form Form { get; set; }
public ReportValues ReportValues { get; set; }
public Report Report { get; set; }
}
In your view you can access your three classes and their properties as you would in your controller. Model.Form.Id
Depending on your data types, ReportValues will likely be a property of Report, but that's entirely up to your data structure. You will need to populate the classes using whatever method you want (Entity Framework, ADO, etc.) before you can pass them to your view and use them.

How to pass two LINQ joined tables from Controller to View

I have three objects:
public class Part
{
[Key]
public int ID { get; set; }
public string Number { get; set; }
public string Name { get; set; }
public int descID { get; set; }
}
public class Description
{
[Key]
public int descID { get; set; }
public string descName { get; set; }
public string description { get; set; }
}
public class GridPart
{
public string name{ get; set; }
public string number { get; set; }
public string description { get; set; }
}
I'm using LINQ to join Part and Description on the descID column:
public ActionResult Index()
{
var myParts = from p in db.Parts
join d in db.Description on p.descID equals d.DescriptorID
select new { Description = d.description, Name = p.name};
List<GridPart> partsList = new List<GridPart>();
foreach (var m in myParts)
{
GridPart gp = new GridPart();
gp.Name = m.name;
gp.description = m.description;
partsList.Add(gp);
}
return View(partsList);
}
If I was just using the Parts table, in the view I would do:
#model IEnumerable<MyApp.Models.Part>
What do I do if I'm using the joined table? This uses both Parts and Description, not to mention my List of GridParts, how do I pass this through to display all of the data I need?
Any advice is greatly appreciated.
If you pass an anonymous type to your view it won't be strongly typed. You can refer to your model like this instead
#Html.TextBox("Name")
or
#Html.Display("Name")
Although this will work I would advice against it - The better solution would be to go with a Viewmodel instead. This will make your view strongly typed.
Edit: Looking on this again I see that your actually not parsing the anonymous type to your view. Your parsing a list of GridParts.
You should be able to strongly type your view like your tried - just refer to GridParts instead of parts.
#model IEnumerable<MyApp.Models.GridPart>

ASP MVC, mutiple models with single controller / view with EF

Can someone explain to me how to use multiple models with a single view in which each of the models represent a DB table?
What I've currently done is created a model file for each model.
Example Model:
[Table("Order")]
public class OrderModel
{
[Key, Column(Order = 0)]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int OrderID { get; set; }
[Key, Column(Order = 1)]
public int UserID { get; set; }
public UserProfile Account { get; set; }
public DateTime Date { get; set; }
public int ShipLocation { get; set; }
public string PONumber { get; set; }
public int StatusID { get; set; }
public StatusModel Status { get; set; }
}
Here is the other model that encompases all the models to use in a single controller / view.
public class OrderPlacementModel
{
public OrderModel OrderChild { get; set; }
public OrderItemsModel OrderItemsChild { get; set; }
public StatusModel StatusChild { get; set; }
public MaterialsModel MaterialsChild { get; set; }
public CategoryModel CategoryChild { get; set; }
public PackModel PackChild { get; set; }
}
public ActionResult PlaceOrder()
{
var viewModel = new OrderPlacementModel
{
OrderChild = new OrderModel(),//or fetch this object from your data source
OrderItemsChild = new OrderItemsChild(),
//...etcetera
};
return View(viewModel);
}
Edit
Or, if you've strongly typed your view to a List<OrderPlacementModel> instead of a single instance, you could do something similar to this:
public ActionResult PlaceOrder()
{
var viewModel = new List<OrderPlacementModel>();
var model = new OrderPlacementModel
{
OrderChild = new OrderModel(),//or fetch this object from your data source
OrderItemsChild = new OrderItemsChild(),
//...etcetera
};
viewModel.Add(model);
//lather, rinse, repeat for however many instances you need to send to your view.
return View(viewModel);
}
Ideally, you should create a view model for the view that encompasses the fields from each model that you need to expose via the view. You can then map these in your controller. I would keep your mapping classes completely ignorant of your view models. Keep your views independent of your data model.
public class OrderViewModel
{
public int OrderId { get; set; }
public int UserId { get; set; }
public DateTime Date { get; set; }
public int ShippingLocation { get; set; }
public List<ItemViewModel> Items { get; set; }
}
public class ItemViewModel
{
public int ItemId { get; set; }
public int Title { get; set; }
}
Note how I have created a view model for the order and - to allow the order have multiple items - have separated these out into a separate model class. Now, you can type your view to OrderViewModel and use as many instances of ItemViewModel as your require.
You can then map your viewmodels to database entities from your controller:
[HttpPost]
public ActionResult ConfirmOrder (OrderViewModel model)
{
if (ModelState.IsValid)
{
foreach (ItemViewModel item in model.Items)
{
/* Create instance of OrderItemsModel (or whatever your
DB mapping class is), populate with appropriate data
from 'item' and commit to database. */
}
OrderModel order = new OrderModel();
order.OrderId = model.OrderId;
order.UserId = model.UserId;
order.Date = model.Date;
order.ShipLocation = model.ShippingLocation;
/* TODO: Commit new order to database */
}
}
Doing things this way adds a little overhead to your initial development time but allows you a great deal more flexibility as you aren't forced to mould all of your views to the shape of your entity classes.

LINQ to entities against EF in many to many relationship

I'm using ASP.NET MVC4 EF CodeFirst.
Need help to write LINQ (to entities) code in Index action to get collection of Courses which are attended by selected student. The relationship is many to many with join table with payload.
//StudentController
//-----------------------
public ActionResult Index(int? id)
{
var viewModel = new StudentIndexViewModel();
viewModel.Students = db.Students;
if (id != null)
{
ViewBag.StudentId = id.Value;
// *************PROBLEM IN LINE DOWN. HOW TO MAKE COURSES COLLECTION?
viewModel.Courses = db.Courses
.Include(i => i.StudentsToCourses.Where(t => t.ObjStudent.FkStudentId == id.Value));
}
return View(viewModel);
}
The error I got is:
The Include path expression must refer to a navigation property defined on the type. Use dotted paths for reference navigation properties and the Select operator for collection navigation properties.
I have modeles (the third one is for join table with payload):
//MODEL CLASSES
//-------------
public class Student
{
public int StudentId { get; set; }
public string Name { get; set; }
public virtual ICollection<StudentToCourse> StudentsToCourses { get; set; }
}
public class Course
{
public int CourseId { get; set; }
public string Title { get; set; }
public virtual ICollection<StudentToCourse> StudentsToCourses { get; set; }
}
public class StudentToCourse
{
public int StudentToCourseId { get; set; }
public int FkStudentId { get; set; }
public int FkCourseId { get; set; }
public string Classroom { get; set; }
public virtual Student ObjStudent { get; set; }
public virtual Course ObjCourse { get; set; }
}
Then, here is modelview I need to pass to view
//VIEWMODEL CLASS
//---------------
public class StudentIndexViewModel
{
public IEnumerable<Student> Students { get; set; }
public IEnumerable<Course> Courses { get; set; }
public IEnumerable<StudentToCourse> StudentsToCourses { get; set; }
}
EF does not support conditional include's. You'll need to include all or nothing (ie no Whereinside the Include)
If you need to get the data for just certain relations, you can select it into an anonymous type, something like (the obviously untested);
var intermediary = (from course in db.Courses
from stc in course.StudentsToCourses
where stc.ObjStudent.FkStudentId == id.Value
select new {item, stc}).AsEnumerable();
Obviously, this will require some code changes, since it's no longer a straight forward Course with a StudentsToCourses collection.

MVC model duplication

I'm very new to ASP.NET MVC, so forgive me if this is something I should know. I haven't seen any obvious documentation on it, so here goes:
I have a LINQ to Entities data model and a MVC project. I use a lot of javascript/jquery, so have opted to access my data from the client through a WebAPI as json objects. However, I don't want to pass all the entity object properties though to the client, so I have added separate models to my MVC project in which I handle MVC model validation and Binding to my Views. Also, in order to work with it in my jquery, I have created json versions of the models.
This is only the start of the project and I don't want to start it off on the wrong foot. Having three versions of my models for each entity in my business layer is going to be a nightmare! I am sure that the overall structure of my project is a very common one, but can't see many developers settling for such duplication of code. There must be a better way of implementing it.
Any thoughts? Really appreciate any input.
In answer to your comment above - you can create your javascript viewmodel as a standard js object. I tend to use Knockout.js so it would look like this:
jsController.Resource = function (data) {
self.UserId = ko.observable(data.UserId);
self.FullName = ko.observable(data.Name);
self.RoleName = ko.observable(data.RoleName);
self.RoleId = ko.observable(data.RoleId);
}
and then use an ajax post method to post it to your MVC action
jsController.addToUndertaking = function (resource, isAsync) {
mylog.log("UndertakingId at post = " + jsController.undertakingId);
var action = $.ajax({
type: "POST",
url: "/TeamMember/AddUserToUndertaking",
data: resource,
cache: false,
async: isAsync
});
action.done(function () {
resource.AllocatedToUndertaking(true);
//Do other funky stuff
});
};
Create your MVC action so that it accepts a forms collection as so:
public ActionResult AddUserToUndertaking(FormCollection postedResource)
{
if (Request.IsAjaxRequest() == false)
{
const string msg = "Non ajax request received";
Logger.ErrorFormat(msg);
throw new SecurityException(msg);
}
if (postedResource == null)
{
Logger.Debug("Null resource posted - terminating.");
return new HttpStatusCodeResult(500);
}
var resource = new AllocatedResourceAjaxViewModel(postedResource);
//Do something Funky
return new HttpStatusCodeResult(200);
}
and then you create your MVC viewmodel from the forms collection (i tend to do this by passing in the forms collection as a constructor method to the viewmodel).
public class AllocatedResourceAjaxViewModel
{
public int UserId { get; set; }
public string Name { get; set; }
public string RoleName { get; set; }
public int RoleId { get; set; }
public AllocatedResourceAjaxViewModel()
{}
public AllocatedResourceAjaxViewModel(NameValueCollection formData)
{
UserId = JsFormDataConverter.Int(formData["UserId"]);
Name = Convert.ToString(formData["FullName"]);
RoleName = Convert.ToString(formData["RoleName"]);
RoleId = JsFormDataConverter.Int(formData["RoleId"]);
}
}
As a null int in your javascript VM will lead to a string of 'undefined' being passed you need a converter method to safely extract non strings.
public static class JsFormDataConverter
{
public static bool Boolean(string formValue, bool defaultValue = false)
{
if (formValue.ToLower() == "true") return true;
if (formValue.ToLower() == "false") return false;
return defaultValue;
}
public static int Int(string formValue, int defaultValue = 0)
{
int result;
return int.TryParse(formValue, out result)
? result
: defaultValue;
}
}
and there you go. I am sure you can improve on the above but that will get you going.
The way that I have always worked is that you have your Models e.g. Order & OrderLines which are where you store all your data and get hydrated either directly from the database by SQL or (more usually these days ) by an ORM such as NHibernate or Entity Framework.
You then have ViewModels - these are used to transport the data from your application to the views - either directly ie a strongly typed view bound to say an OrderViewModel or via an action returning a JsonResult.
A OrderViewModel is not a duplication of Order as it is designed to only hold the data that is needed to be presented on the screen (If you have many different views displaying an Order in different ways it could be perfectly acceptable to have many different ViewModels -one for each view containing only the fields needed for each view). ViewModels should also not contain any complex types except other ViewModels. this helps keep accidental data access out of the views (think security and performance).
So Given
public class Order
{
public int Id { get; set; }
public DateTime OrderDate { get; set; }
public User User { get; set; }
public string Description { get; set; }
public List<OrderLine> OrderLines { get; set; }
}
public class OrderLine
{
public int Id { get; set; }
public Order Order { get; set; }
public String Description { get; set; }
public int Quantity { get; set; }
public int Weight { get; set; }
public int Price { get; set; }
}
public class User
{
public int Id { get; set; }
public string Name { get; set; }
}
You could have the two ViewModels
public class OrderViewModel
{
public int ID { get; set; }
public List<OrderLineViewModel> OrderLines { get; set; }
public DateTime OrderDate { get; set; }
public int UserId { get; set; }
public string Description { get; set; }
}
public class OrderLineViewModel
{
public int Id { get; set; }
public int OrderId { get; set; }
public String Description { get; set; }
public int Quantity { get; set; }
public int Weight { get; set; }
public int Price { get; set; }
}
The view models could then be serialized into JSON as needed or marked up with validation attributes etc.

Resources